High-Throughput Synthesis of Nanogap-Rich Gold Nanoshells Using Dual-Channel Infusion System.

Gold nanoshells have been actively applied in industries beyond the research stage because of their unique optical properties. Although numerous methods have been reported for gold nanoshell synthesis, the labor-intensive and time-consuming production process is an issue that must be overcome to meet industrial demands. To resolve this, we report a high-throughput synthesis method for nanogap-rich gold nanoshells based on a core silica support (denoted as SiO ₂ @Au NS), affording a 50-fold increase in scale by combining it with a dual-channel infusion pump system. By continuously dropping the reactant solution through the pump, nanoshells with closely packed Au nanoparticles were prepared without interparticle aggregation. The thickness of the gold nanoshells was precisely controlled at 2.3-17.2 nm by regulating the volume of the reactant solution added dropwise. Depending on the shell thickness, the plasmonic characteristics of SiO ₂ @Au NS prepared by the proposed method could be tuned. Moreover, SiO ₂ @Au NS exhibited surface-enhanced Raman scattering activity comparable to that of gold nanoshells prepared by a previously reported low-throughput method at the same reactant ratio. The results indicate that the proposed high-throughput synthesis method involving the use of a dual-channel infusion system will contribute to improving the productivity of SiO ₂ @Au NS with tunable plasmonic characteristics.